I'd pick a trailer any day. I have both and have towed quite a bit with my dolly. Longest trip I made with a dolly was 60 miles. It works great for loading when by myself, but I wouldn't go too far again and I certainly would maintain lower speeds, especially when my tow vehicle is not MUCH heavier than the towed vehicle. Just for giggles, hook up a vehicle on your tow dolly and tow it down gravel roads and make a few turns. You will quickly find out how stable or unstable it is.
